Two conductive polymers PERCOL(copyright) 292, (copolymer of a quaternary acrylate salt and acrylamide, Allied Colloids, Inc.) and VERSICON(copyright), (Polyaniline)(Emeraldine salt), green/black powder, Monsanto Company) were evaluated in a potential minimum signature tactical missile propellant formulation. Tactical minimum signature propellants rely heavily on the energetic nitramines to achieve high performance. Energetic nitramines are the major ingredients used in most minimum signature propellant formulations, in missile warheads and for gun propellant applications. The most widely used energetic nitramines RDX (trimethylene trinitramine) and HMX (tetramethylene tetranitramine) are very sensitive to impact and friction stimili. Propellants formulations containing high percentages of RDX and HMX are all very sensitive to impact and friction stimuli.
The purpose of evaluating conductive polymers was to determine if static electricity buildup within the propellant formulation had any effect on the friction and impact properties of a minimum signature propellant.
Conductive Polymers (PERCOL(copyright) 292 and VERSICON(copyright)) were added to a typical minimum signature propellant and the propellant formulation was evaluated for impact and friction sensitivity. These two conductive polymers evaluated are described in Table I. The minimum signature propellant formulation used in the initial evaluations is outlined in Table II. The results obtained in these experiments can apply to both warhead and gun propellant formulations that contain higher percentages of the energetic nitramines RDX and HMX.
The results of the findings were compared to a baseline formulation containing no antistatic agent. The results of these findings are outlined in Table III. The PERCOL(copyright) 292 improved the friction insensitivity significantly at the one percent level. This increase in friction was superior to the results achieved with VERSICON(copyright) at the same percent level. However, the VERSICON(copyright) improved impact insensitivity properties at the one half percent concentration while the PERCOL(copyright) 292 made the propellant more sensitive to impact. At the one-half and one percent concentrations of the conductive polymers, performance of the propellant was sacrificed. The lower concentrations of polymers are more desirable to achieve improvements in impact and friction insensitivity while maintaining high performance.